Download MendeleyCradle loop regulates beta-barrel pore-formation mechanism of Vibrio cholerae cytolysin.
Singh, M., Chatterjee, A., Nayak, A., Naskar, P., Kaur, G., Mondal, J., Dutta, S., Chattopadhyay, K.(2025) Structure
- PubMed: 41202807
- DOI: https://doi.org/10.1016/j.str.2025.10.013
- Primary Citation of Related Structures:
9LH3, 9LH7, 9UE9 - PubMed Abstract:
Vibrio cholerae cytolysin (VCC) is a β-barrel pore-forming toxin (β-PFT). The membrane insertion of its pore-forming "pre-stem" motif is the most crucial step in the pore-formation mechanism. In the soluble monomeric form, pre-stem remains clamped against the central cytolysin domain by the so-called cradle loop. In the course of oligomeric pore-formation in the target membranes, the cradle loop gets detached from the pre-stem and reorients, thus allowing the pre-stem to extend and insert into the membrane. Here, we show that the specific cradle loop residue(s) play crucial roles in governing the pore-formation mechanism of VCC by establishing decisive interactions with the neighboring structural domains/modules. The alteration of the cradle loop residue, Y194 in particular, compromises the membrane-insertion of the pre-stem, and tends to arrest the membrane-bound toxin in the pre-pore-like oligomeric states. Our study suggests that the native cradle loop architecture, with its intact contacts with the surrounding interaction partners, is essential for VCC pore-formation.
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali, Punjab 140306, India.
Organizational Affiliation:
